In the stopping distance formula, what does R.D stand for?

• A. Braking Distance
• B. Stopping Distance
• C. Reaction Distance
• D. Relative Distance

Answer: (C)

The stopping distance is made up of two parts: the distance you travel while reacting to a hazard and the distance you travel while your brakes are applied. R.D stands for Reaction Distance—the distance covered from the moment you see the hazard until you actually press the brakes. This distance grows with higher speeds, since you’re moving faster, and with longer reaction times caused by distraction, fatigue, or impairment. The braking distance is the second part, the distance to come to a stop once braking begins, and it depends on factors like vehicle condition, tire grip, road surface, and weather. Relative distance isn’t a term used in this formula, and stopping distance refers to the total of both parts.